Large area OLED display

Abstract

An active matrix organic LED display having a matrix of multiple light emitting pixels and electronic drive circuitry for selectively addressing the pixels, each pixel containing an organic LED. The electronic drive circuitry includes row scan electrodes and column data electrodes that interconnect the matrix of pixels. The circuitry also includes a MEMS switching device and a memory capacitor for each pixel, the MEMS switching device connecting the memory capacitor to a column data electrode during addressing of a pixel and connecting the memory capacitor to the organic LED of each pixel during light emission.

The invention claimed is: 
     
       1. An active matrix organic LED pixel display having a multiplicity of light-emitting sub-pixels and electronic drive circuitry for selectively addressing said sub-pixels, each sub-pixel containing an organic LED, said display comprising a matrix of sub-pixels connected by row scan electrodes and column data electrodes, each sub-pixel having a MEMS switching device and a memory capacitor, said MEMS switching device connecting the memory capacitor to the column data electrodes during the addressing and to the organic LED during light emission, a ramp circuit connected to the row electrodes to provide a ramp voltage to the row electrodes to control the rate of capacitor discharge through the organic LED, a precise amount of charge to each sub-pixel's memory capacitor being dissipated by the ramp circuit to control the forward current rate through the organic LED to produce light output. 
     
     
       2. The invention of  claim 1  wherein a metal electrode at least partially covers the front surface of the display so as to at least partially encapsulate the front surface of the organic LED layers and prevent oxygen and humidity diffusing into the organic LED layers from the front surface. 
     
     
       3. The invention of  claim 1  wherein the switching device is a Bimorph MEMS switching device. 
     
     
       4. The invention of  claim 1  wherein a metal electrode completely covers the front surface of the display so as to encapsulate the front surface of the organic LED layers and prevent oxygen and humidity diffusing into the organic LED layers from the front surface.